Metal tool



UNITED STATES PATENT OFFCE.

EVRAH C. LIPPS, OF DETROIT, lIICI-IIGAN, ASSIGNOR TO PACKARD MOTOR CARCOM- PANY, OF DETROIT, MICHIGAN,

A CORPORATION OF MICHIGAN.

METAL TOOL.

Specification of Letters Patent.

Patented Dec. 6, 1921.

Original application led November 9, 1917, Serial No. 201,143. Dividedand this application filed January 22, 1920. Serial No. 353,350.

To all whom t may concern:

Be it known that I, EVRAH C. Lirrs, a citizen of the United States, andresiding at Detroit, Vayne county, State of Michigan, have inventedcertain new and useful Improvements in Metal Tools, of -which thefollowing is a speciiication.

The present application which is a division of my application 201,143filed Nov. 9, 1917, relates to the art of metal working and moreparticularly to a tool made by integrally uniting a plurality of piecesof metal.

Heretofore, as far as I am aware, it has not been possible toelectrically weld by the resistance method two pieces which differ insize or properties, by a series of spot welds, where the weld desiredexceeds in area the capacity of the machine. In other words a machinehaving a capacity to weld an area up to one square inch, could not beutilized to weld an area of four square inches by` making foursuccessive welds. 1Where the pieces differ in size, or properties suchas the specific electrical resistance, one of the pieces will reach awelding heat and burn before the other reaches such heat, if indeed thelatter piece reaches a weld heat at, all. According to the presentinvention, however, these difficulties have been overcome so that pieceshaving different characteristics as mentioned above may be integrallyjoined by a series of electrical spot welds, to form a tool or otherinstrument.

The objects and features of the invention will be apparent from thedescription taken in connection with the drawings in which:

Figure 1 is a perspective view showing a piece of metal adapted to formthe stock of a tool, prepared to have a second piece welded thereto, thepreparation consisting in forming grooves, slots, or air gaps;

Fig. 2 is a perspective view showing the two pieces welded together andone of the air gaps filled up;

Fig. 3 is another perspective view illustrating the tool form-ed fromthe weldedtogether-pieces; and

Fig. 4 is a partial plan View showing an alternative method of preparingthe piece of metal or stock shown in Fig. 1.

Referring to the drawings, a piece of metal 10, which is shown asadapted for the body of an instrument, is formed with a seat 11 at anedge portion thereof to receive another piece of metal 12. In the caseof `a tool the body may be a cheaper low grade steel such as a carbon,machinery, or cheap alloy steel and the piece 12'is preferably a wearresisting steel such as a high speed or higher grade alloy steel.Extending transversely of the seat are a plurality of spaced grooves,slots or air gaps 13, thus dividing a portion of the piece 10 intosections 14. The slots 13 act to electrically and thermally insulate thesections 14 from each other. The stock of the tool may be formed withholes 15 to cooperate with pins or bolts to hold the same in a machine.

In order to join the piece 12 of'alloy or high speed steel to the stock,the former is placed on the seat 11 of the stock and the two piecessecured in an electric welding machine, one terminal of the weldingcircuit being connected to a section 14 and the other terminal beingplaced on the piece 12 directly over the said section, the machinehaving at least a capacity to weld an area equal to the top surface ofthe section. The circuit is then closed andthe current passing from thesection 14 through the piece 12 raises the contacting surfaces towelding heat and fuses them together. The size of the sections 14, or inother wor-ds, the number of air gaps formed in the stock to extendtransversely of the piece 12 depends on the capacity of the machine, thesections being formed as to provide welding surfaces within the capacityof the machine.

After having welded together one of the sections 14 and the piece 12,the other sections are successively weldedto the piece 12. The resultingproduct is illustrated in Fig. 2, and may be machined cr worked to givea tool of any desired shape, one form being shown in Fig. 3.

If it is desired to compensate for the loss of strength due to the slots13, they may be filled up with a suitable material, as shown at 16 inFigs. 2 and 3. If a metal filler is used it may be welded to thesurrounding metal by the acetylene process or in any other desiredmanner.

Instead of preparing the piece 10 by slotting the same, I may form rowsof closely spaced small holes 17 as shown in Fig. 4, thereby dividingthe piece into the sections Vpieces are .of different sizes.

14. The small piece of steel may. then-be welded to the body in the samemanner as is described above. The resulting weld is entirelysatisfactory.V Furthermore the `product is stronger than where slots areemployed as the holes do not weaken the body piece as much.

From the foregoing description, it will be seen that `the Vpresentinvention comprises an article such as a tool consisting oftwo pieces ofmetal integrally joined by a series of spot `welds, the smaller piece ofone grade of steel being welded to the larger piece or stock of .anotheror cheaper grade of steel. Thespelciic electrical resistance of highspeed or `similar alloy steel is greater than that of carbon or cheaperalloy steels. Because of this property, the current passing through thepieces tends to heat the low grade steel first, where the slots of myinvention are not employed.` Moreover in cases where it is desired toweld a small piece of metal to a `larger piece, the small piece heatsfirst and burns before the large `piece reachesV a'weld- `ing heat. M`invention therefore is .particularly app icable where it is desired tojoin two pieces ofdilferent electrical resistances by a series of spotwelds7 or-where the It is to be -understood however that theinvention'is not limited to these two cases or a combination of them,but is applicable to many other cases `within the `scope of the appendedclaims.

Having thus described the invention what is claimed as new and desiredtobe secured by Letters Patent is :V y

l. An `article of manufacture comprising a machinery steel body having.a seat at one end `thereof with a transverse slot7 and ,piece of highspeed steel on said seat eX- erding across said slot and welded to said2y A tool comprising 'a steel stock having aslot therein, and a piece ofa diderent grade of steel welded to said stock extending across saidslot.

3. A tool comprising a steel stock having a slot therein, a .piece :ofhigh `speed steel welded-to-said stock extending over said slot, and afiller in said slot.

4. A tool comprising two metal pieces havfing different electricalresistances, the piece having the lower resistance formed with a slottherein and. the other' ypiece integrally vsecuredto the slotted pieceand extending transversely to the slot.

An article of manufacture comprising a ymetal body having a portionvdivided 'into sections, and apiece of different. kind of v.metal weldedto said sections.

randa filler in said slot weldedto the stock.

2 7. An article of `manufacture comprising -a steel body having a slottherein and a piece of alloyfsteelwelded to said body extendingacrosslsaid slot.

`8. An article of lmanufacture comprising .a metal body having a slottherein and a :piece of a different grade/ofthe same metal vlelded to'said 'body extending across said s ot. f

9. An article of manufacture comprising a body of low grade steel havinga slottherein `and a piece of higher grade steel welded to saidbodyzextending .across saidslot.

In testimonywhereof I aflixmy signaturel Y EVRAH C. LIPPS

